Silicone hydrogel reactive mixtures comprising borates

ABSTRACT

Disclosed in this specification is a method for forming a silicone hydrogel material that is useful for forming contact lens materials. The method includes using an effective amount of a borate additive to reduce the gel time of the silicone hydrogel reactive mixture and/or enhance the optical properties of the resulting cured material.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application61/410,003 filed Nov. 4, 2010.

FIELD OF THE INVENTION

This invention relates, in at least one embodiment, to a method offorming a silicone hydrogel contact lens material.

BACKGROUND OF THE INVENTION

Silicone hydrogels are typically formed by curing blends of siliconemonomers or macromers and hydrophilic monomers. In many cases, theblends of the desired silicone monomers with hydrophilic monomers arenot miscible. The immiscible blends are opaque and cannot be used toform a material suitable for use in a contact lens.

One solution to the problem of immiscible blends involves the use ofspecialized diluents, including secondary and tertiary alcohols as welldiluents which balance solubility and hydrogen bonding parameters.

Previous attempts to address the immiscibility problem rely oncompatabilizing otherwise insoluble blends so that optically clearlenses can be formed. These attempts generally do not provide abeneficial effect on other characteristics of the reaction mixture suchas viscosity, rate of curing or the mechanical properties of theresulting contact lens.

SUMMARY OF THE INVENTION

The invention comprises, in one form thereof, a method of forming asilicone hydrogel contact lens material by curing a reaction mixturethat includes at least one hydrophilic component, at least one siliconecomponent and at least one borate additive. In some cases the additionof a borate additive increases the viscosity of the mixture, or itreduces the gel time needed to cure the mixture while maintaining anoptically clear blend.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is disclosed with reference to the accompanyingdrawings, wherein:

FIG. 1 is a graph showing heat flow from curing a control sample;

FIG. 2 is a graph showing heat flow from curing a borate-treated sample;

FIG. 3 is a graph showing heat flows for examples 11 to 13;

FIG. 4 is a dynamic mechanical analysis of blend 17; and

FIG. 5 is a dynamic mechanical analysis of blend 20.

Corresponding reference characters indicate corresponding partsthroughout the several views. The examples set out herein illustrateseveral embodiments of the invention but should not be construed aslimiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

The use of borate ester-containing diluents has been described for theformation of convention hydrogels that do not contain silicone. See, forexample, U.S. Pat. Nos. 4,889,664 and 5,039,459. However, it hasunexpectedly been found that borates can be used in silicone hydrogelprecursor mixtures and that such formulations beneficially alter certainproperties of the precursor mixtures (viscosity and rate of curing) andthe properties of the resulting lenses such as optical clarity.

The invention generally pertains to a method of forming a siliconehydrogel material that includes a polymerizable hydrophilic component, apolymerizable silicone component and an additive with borate esterfunctionality. At least one of the components includes a hydroxyl groupcapable of forming a borate ester group.

A “reaction mixture” is the mixture of components, including, reactivecomponents such as monomers and macromer, diluent, initiators,crosslinkers and additives which, when subjected to polymer formingconditions, form a polymer. Reactive components are the components inthe reaction mixture, which upon polymerization, become a permanent partof the polymer, either via chemical bonding or entrapment orentanglement within the polymer matrix. For example, reactive componentsbecome part of the polymer via polymerization, while polymeric internalwetting agents without polymerizable groups, such as PVP (polyvinylpyrrolidone), become part of the polymer via entrapment. The diluent andany additional processing aids do not become part of the structure ofthe polymer and are not part of the reactive components. Such componentsare removed during the manufacturing process. Applications of suchsilicone hydrogel materials include contact lenses, bandage lenses,intraocular lenses, as well as a variety of other medical devices.

A hydrogel is a hydrated crosslinked polymeric system that containswater in an equilibrium state. When the hydrogels of the presentinvention are used to form contact lenses they absorb at least about 10wt % water.

A “biomedical device” or “medical device” is any article that isdesigned to be used while either in or on mammalian tissues or fluid.Examples of these devices include but are not limited to wounddressings, catheters, implants, stents, and ophthalmic devices such asintraocular lenses and contact lenses. In one embodiment the biomedicaldevices are ophthalmic devices, particularly contact lenses, mostparticularly contact lenses made from silicone hydrogels.

A “contact lens” refers to ophthalmic devices that reside in or on theeye. These devices can provide optical correction, cosmetic enhancement,UV blocking and visible light or glare reduction, therapeutic effect,including wound healing, delivery of drugs or nutraceuticals, diagnosticevaluation or monitoring, or any combination thereof. The term lensincludes, but is not limited to, soft contact lenses, hard contactlenses, intraocular lenses, overlay lenses, ocular inserts, and opticalinserts.

-   -   Polymerizable are groups that can undergo free radical and/or        cationic polymerization. Non-limiting examples of free radical        reactive groups include (meth)acrylates, styryls, vinyls, vinyl        ethers, C₁₋₆alkyl(meth)acrylates, (meth)acrylamides,        C₁₋₆alkyl(meth)acrylamides, N-vinyllactams, N-vinylamides,        C₂₋₁₂alkenyls, C₂₋₁₂alkenylphenyls, C₂₋₁₂alkenylnaphthyls,        C₂₋₆alkenylphenylC₁₋₆alkyls, O-vinylcarbamates and        O-vinylcarbonates. Non-limiting examples of cationic reactive        groups include vinyl ethers or epoxide groups and mixtures        thereof. In one embodiment the free radical reactive groups        comprises (meth)acrylate, acryloxy, (meth)acrylamide, and        mixtures thereof.

As used in this specification, the term “(meth)” designates optionalmethyl substitution. Thus, a term such as “(meth)acrylate” denotes bothmethacrylic and acrylic radicals.

As used in this specification, the term borate refers to an esterbetween boric acid and an alcohol, and comprises —B—O—C— structure. Theborate does not become a permanent part of the polymeric matrix (e.g.while it may react with hydroxyl containing components in the reactivemixture, the bonds are labile and easily hydrolyzed when the polymer iscontacted with water). Instead, the borate group is part of the diluentsystem and does not become a permanent part of the final lens. Theborate is typically removed from the polymerized material prior tocommercial use. Examples of borates include borate esters such astrimethyl borate, triethyl borate, tri-n-propyl borate, tri-isopropylborate, tri-butyl borate, and tri-tert-butyl borate and triHEMA borate.Borate esters are generally of the formula:

where R₁, R₂ and R₃ are hydrocarbons. In one embodiment, thehydrocarbons are monovalent alkyl or aryl groups. In another embodiment,two of the groups are divalent groups that are covalently bonded to oneanother, thereby forming a cyclic borate ester. In one embodiment, thethree hydrocarbon groups are identical. In another embodiment, the threehydrocarbon groups are independently determined, and thus are notidentical. In yet another embodiment, at least one of the hydrocarbongroups is a polymerizable component, for example, if the R group on theborate ester is derived from a hydroxyl-functional reactive monomer likeHEMA, which would form mono-, di- or triHEMA borate. In anotherembodiment R1, R2 and R3 are independently derived from monofunctionalalcohols.

In another embodiment, at least one of the hydrocarbons can be one ofthe polymerizable components used in the formation of the siliconehydrogel. After benefiting from the disclosure contained in thisspecification, other sources of borates would be readily apparent andare contemplated for use with the present invention. In some embodimentsit is desirable to add concentrations of borates which do not result infree borates in the reaction mixture. Thus, in some embodiments suitableamounts of borate may be determined on a molar basis by calculating themolar percentage of hydroxyl groups where the hydrogen has beentemporarily replaced with a borate compared to all hydroxyl groups andborate substituted hydroxyls and include from about 5 molar % OH (molepercent —B—O—C— functionality relative to combined —C—O—H and —B—O—C—functionality) to about 100 molar % OH based upon all hydroxyls in thereactive mixture and diluents, and in another embodiment between about10 and about 80 molar % OH, and in yet another embodiment about 15 toabout 70%. The molar % OH needed varies from system to system. Molar %OH should not be so high that the reactive mixture gels prior topolymerization. For example, in systems containing polyhydroxylmacromers such as HFM, with little or no mono-hydroxyl components (suchas HEMA), the molar % OH fo 25% caused undesirable gelation. Molar % OHin these systems are accordingly less than about 25 molar % OH and insome embodiments from about 3 to about 20 molar % OH. In systemscomprising substantial quantities of mono-hydroxyl components the molar% OH may be as high as 100%. An example of this calculation is includedin paragraph [0081] herein.

As used herein, the notation —C—OH or —C—O—H, refers to a hydroxyl groupwhich is attached to a carbon atom in a molecule, and thus, excludes —OHwhich is part of water. Similarly, —B—O—C— denotes a borate ester groupcontained within a molecule. Generally, the moles of —B—O—C—functionality per gram of blend are calculated. Similarly, the moles of—C—O—H functionality (including the mmoles of —B—O—C—) per gram of blendare calculated. Dividing the millimoles —B—O— by the combined millimoles—O—H and —B—O—C— (“mmole OH”), and multiplying times 100, provides themolar % OH.

As used in this specification, the phrase “hydrophilic component” refersto a monomer or macromer that, when polymerized with crosslinker, haswater content of at least about 10%. Examples of hydrophilic componentsinclude HEMA (2-hydroxyethyl methacrylate), DMA(N,N-dimethylacrylamide), GMA(glycerol methacrylate), 2-hydroxyethylmethacrylamide, polyethyleneglycol monomethacrylate, methacrylic acid,acrylic acid, N-vinyl pyrrolidone, N-vinyl-N-methyl acetamide,N-vinyl-N-ethyl acetamide, N-vinyl-N-ethyl formamide, N-vinyl formamide,combinations thereof and the like. Further examples of hydrophiliccomponents are disclosed in U.S. Pat. No. 6,822,016, the content ofwhich is hereby incorporated by reference into this specification. Afterbenefiting from reading this specification, other hydrophilic componentswould be readily apparent to one skilled in the art and such componentsare contemplated for use with the present invention. Suitable amounts ofhydrophilic component include about 5 to about 80%.

As used in this specification, the phrase “silicone component” refers toa siloxane-containing monomer or macromer. Examples include reactivepolydialkylsiloxanes, such as monomethacryloxypropyl terminatedmono-C1-C5 alkyl terminated polydimethylsiloxane. Suitable examplesinclude monomethacryloxypropyl terminated mono-methyl terminatedpolydimethylsiloxane, monomethacryloxypropyl terminated mono-n-butylterminated polydimethylsiloxane, with a molecular weight from 800-1000or OH— mPDMS—mono-(3-methacryloxy-2-hydroxypropyloxy)propyl terminated,mono-butyl terminated polydimethylsiloxane)

where n is 1-200.

Other examples of silicone components include

where a is 10-500 and b is 1-150.

Other examples of silicone components include 2-propenoic acid,2-methyl-,2-hydroxy-3-[3-[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]disiloxanyl]propoxy]propylester (SiGMA).

Still other suitable silicone components include compounds of Formula I

-   -   where

R¹ is independently selected from monovalent reactive groups, monovalentalkyl groups, or monovalent aryl groups, any of the foregoing which mayfurther comprise functionality selected from hydroxy, amino, oxa,carboxy, alkyl carboxy, alkoxy, amido, carbamate, carbonate, halogen orcombinations thereof; and monovalent siloxane chains comprising 1-100Si—O repeat units which may further comprise functionality selected fromalkyl, hydroxy, amino, oxa, carboxy, alkyl carboxy, alkoxy, amido,carbamate, halogen or combinations thereof;

where b=0 to 500, where it is understood that when b is other than 0, bis a distribution having a mode equal to a stated value;

wherein at least one R¹ comprises a monovalent reactive group, and insome embodiments between one and 3 R¹ comprise monovalent reactivegroups.

As used herein “monovalent reactive groups” are groups that can undergofree radical and/or cationic polymerization. Non-limiting examples offree radical reactive groups include (meth)acrylates, styryls, vinyls,vinyl ethers, C₁₋₆alkyhmeth)acrylates, (meth)acrylamides,C₁₋₆alkyl(meth)acrylamides, N-vinyllactams, N-vinylamides,C₂₋₁₂alkenyls, C₂₋₁₂alkenylphenyls, C₂₋₁₂alkenylnaphthyls,C₂₋₆alkenylphenylC₁₋₆alkyls, O-vinylcarbamates and O-vinylcarbonates.Non-limiting examples of cationic reactive groups include vinyl ethersor epoxide groups and mixtures thereof. In one embodiment the freeradical reactive groups comprises (meth)acrylate, acryloxy,(meth)acrylamide, and mixtures thereof.

Suitable monovalent alkyl and aryl groups include unsubstitutedmonovalent C₁ to C₁₆alkyl groups, C₆-C₁₄ aryl groups, such assubstituted and unsubstituted methyl, ethyl, propyl, butyl,2-hydroxypropyl, propoxypropyl, polyethyleneoxypropyl, combinationsthereof and the like.

In one embodiment b is zero, one R¹ is a monovalent reactive group, andat least 3 R¹ are selected from monovalent alkyl groups having one to 16carbon atoms, and in another embodiment from monovalent alkyl groupshaving one to 6 carbon atoms. Non-limiting examples of siliconecomponents of this embodiment include2-methyl-,2-hydroxy-3-[3-[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]disiloxanyl]propoxy]propylester (“SiGMA”),2-hydroxy-3-methacryloxypropyloxypropyl-tris(trimethylsiloxy)silane,3-methacryloxypropyltris(trimethylsiloxy)silane (“TRIS”),3-methacryloxypropylbis(trimethylsiloxy)methylsilane and3-methacryloxypropylpentamethyl disiloxane.

In another embodiment, b is 2 to 20, 3 to 15 or in some embodiments 3 to10; at least one terminal R¹ comprises a monovalent reactive group andthe remaining R¹ are selected from monovalent alkyl groups having 1 to16 carbon atoms, and in another embodiment from monovalent alkyl groupshaving 1 to 6 carbon atoms. In yet another embodiment, b is 3 to 15, oneterminal R¹ comprises a monovalent reactive group, the other terminal R¹comprises a monovalent alkyl group having 1 to 6 carbon atoms and theremaining R¹ comprise monovalent alkyl group having 1 to 3 carbon atoms.Non-limiting examples of silicone components of this embodiment include(mono-(2-hydroxy-3-methacryloxypropyl)-propyl ether terminatedpolydimethylsiloxane (400-1000 MW)) (“OH-mPDMS”), monomethacryloxypropylterminated mono-n-butyl terminated polydimethylsiloxanes (800-1000 MW),(“mPDMS”).

In another embodiment b is 5 to 400 or from 10 to 300, both terminal R¹comprise monovalent reactive groups and the remaining R¹ areindependently selected from monovalent alkyl groups having 1 to 18carbon atoms which may have ether linkages between carbon atoms and mayfurther comprise halogen.

In another embodiment, one to four R¹ comprises a vinyl carbonate orcarbamate of the formula:

wherein: Y denotes O—, S— or NH—;

R denotes, hydrogen or methyl; and q is 0 or 1.

The silicone-containing vinyl carbonate or vinyl carbamate monomersspecifically include:1,3-bis[4-(vinyloxycarbonyloxy)but-1-yl]tetramethyl-disiloxane;3-(vinyloxycarbonylthio)propyl-[tris(trimethylsiloxy)silane];3-[tris(trimethylsiloxy)silyl]propyl allyl carbamate;3-[tris(trimethylsiloxy)silyl]propyl vinyl carbamate;trimethylsilylethyl vinyl carbonate; trimethylsilylmethyl vinylcarbonate, and Formula III:

Where biomedical devices with modulus below about 200 are desired, onlyone R¹ shall comprise a monovalent reactive group and no more than twoof the remaining R¹ groups will comprise monovalent siloxane groups.

In one embodiment, where a silicone hydrogel lens is desired, the lensof the present invention will be made from a reactive mixture comprisingat least about 20 weight % and in some embodiments between about 20 and70% wt silicone-containing components based on total weight of reactivecomponents from which the polymer is made. Another class ofsilicone-containing components includes polyurethane macromers of thefollowing formulae:(*D*A*D*G)_(a)*D*D*E¹;E(*D*G*D*A)_(a)*D*G*D*E¹ or;E(*D*A*D*G)_(a)*D*A*D*E¹  Formulae IV-VI

wherein:

D denotes an alkyl diradical, an alkyl cycloalkyl diradical, acycloalkyl diradical, an aryl diradical or an alkylaryl diradical having6 to 30 carbon atoms,

G denotes an alkyl diradical, a cycloalkyl diradical, an alkylcycloalkyl diradical, an aryl diradical or an alkylaryl diradical having1 to 40 carbon atoms and which may contain ether, thio or amine linkagesin the main chain;

* denotes a urethane or ureido linkage;

_(a) is at least 1;

A denotes a divalent polymeric radical of formula:

R¹¹ independently denotes an alkyl or fluoro-substituted alkyl grouphaving 1 to 10 carbon atoms which may contain ether linkages betweencarbon atoms; y is at least 1; and p provides a moiety weight of 400 to10,000; each of E and E¹ independently denotes a polymerizableunsaturated organic radical represented by formula:

wherein: R¹² is hydrogen or methyl; R¹³ is hydrogen, an alkyl radicalhaving 1 to 6 carbon atoms, or a —CO—Y—R¹⁵ radical wherein Y is —O—,Y—S— or —NH—; R¹⁴ is a divalent radical having 1 to 12 carbon atoms; Xdenotes —CO— or —OCO—; Z denotes —O— or —NH—; Ar denotes an aromaticradical having 6 to 30 carbon atoms; w is 0 to 6; x is 0 or 1; y is 0 or1; and z is 0 or 1.

In one embodiment the silicone-containing component comprises apolyurethane macromer represented by the following formula:

wherein R¹⁶ is a diradical of a diisocyanate after removal of theisocyanate group, such as the diradical of isophorone diisocyanate.Another suitable silicone containing macromer is compound of formula X(in which x+y is a number in the range of 10 to 30) formed by thereaction of fluoroether, hydroxy-terminated polydimethylsiloxane,isophorone diisocyanate and isocyanatoethylmethacrylate.

Other silicone-containing components suitable for use in this inventioninclude those described is WO 96/31792 such as macromers containingpolysiloxane, polyalkylene ether, diisocyanate, polyfluorinatedhydrocarbon, polyfluorinated ether and polysaccharide groups. Anotherclass of suitable silicone-containing components includes siliconecontaining macromers made via GTP, such as those disclosed in U.S. PatNos. 5,314,960, 5,331,067, 5,244,981, 5,371,147 and 6,367,929. U.S. Pat.Nos. 5,321,108; 5,387,662 and 5,539,016 describe polysiloxanes with apolar fluorinated graft or side group having a hydrogen atom attached toa terminal difluoro-substituted carbon atom. US 2002/0016383 describehydrophilic siloxanyl methacrylates containing ether and siloxanyllinkanges and crosslinkable monomers containing polyether andpolysiloxanyl groups. Any of the foregoing polysiloxanes can also beused as the silicone-containing component in this invention.

After benefiting from reading this specification, other siliconecomponents would be readily apparent to one skilled in the art and suchcomponents are contemplated for use with the present invention.

In the mixture of hydrophilic and silicone components, at least one ofthe components has one or more free hydroxyl groups. In one embodiment,at least one hydrophilic component has at least one hydroxyl group whichmay be converted to borate ester groups. In another embodiment, at leastone silicone component has at least one free hydroxyl group. In yetanother embodiment, both a silicone containing component and ahydrophilic component have at least one free hydroxyl group. Due to thepresence of at least one free hydroxyl group on the components, theresulting polymer is a polyol that contains multiple free hydroxylgroups.

The reaction mixture may further comprise additional components,including, but not limited to ultra-violet absorbing components,reactive tints, pigments, dyes, photochromic compounds, release agents,wetting agents, nutriceutical compounds, pharmaceutical compounds,combinations thereof and the like. Crosslinkers are compounds with twoor more polymerizable functional groups. Examples of crosslinkers thatmay be used in this invention include TEGDMA (tetraethyleneglycoldimethacrylate), TrEGDMA (triethyleneglycol dimethacrylate), EGDMA(ethyleneglycol dimethacylate), acPDMS, combinations thereof and thelike.

The reaction mixtures of the present invention may further comprise atleast one initiator. Initiators include compounds such as lauroylperoxide, benzoyl peroxide, isopropyl percarbonate,azobisisobutyronitrile, and the like, that generates free radicals atmoderately elevated temperatures, photoinitiator systems such as anaromatic alpha-hydroxy ketone and a tertiary amine plus a diketone.Illustrative examples of photoinitiator systems are 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one,bis(2,6-dimethoxybenzoyl)-2,4-4-trimethylpentyl phosphine oxide(DMBAPO), and a combination of camphorquinone and ethyl4-(N,N-dimethylamino)benzoate. The initiator is used in the reactionmixture in catalytically effective amounts, e.g., from about 0.1 toabout 2 parts by weight per 100 parts of reactive component.Polymerization of the reaction mixture can be initiated using theappropriate choice of heat or visible or ultraviolet light or othermeans depending on the polymerization initiator used. Alternatively,initiation can be conducted without a photoinitiator using, for example,low voltage e-beam. However, when a photoinitiator is used, thepreferred initiator is a combination of 1-hydroxycyclohexyl phenylketone and bis(2,6-dimethoxybenzoyl)-2,4-4-trimethylpentyl phosphineoxide (DMBAPO), and the preferred method of polymerization initiation isvisible light.

Diluents useful in preparing the devices of this invention includeethers, esters, alkanes, alkyl halides, silanes and alcohols. In oneembodiment the diluents comprise alcohols, and in another secondary andtertiary alcohols. Examples of ethers useful as diluents for thisinvention include tetrahydrofuran. Examples of esters useful for thisinvention include ethyl acetate. Examples of alkyl halides useful asdiluents for this invention include methylene chloride. Examples ofsiloxanes useful as diluents for this invention includeoctamethylcyclotetrasiloxane. Examples of alcohols useful as diluentsfor this invention include hexanol, heptanol, octanol, nonanol, decanol,tert-butyl alcohol, 3-methyl-3-pentanol, isopropanol, t-amyl alcohol and3,7-dimethyl-3-octanol. Additional diluents useful for this inventionare disclosed in U.S. Pat. No. 6,020,445, which is incorporated hereinby reference.

Without wishing to be bound by any particular theory, applicants believethat when a borate diluent is added to a blend which contains at leastone other hydroxyl-containing compounds an equilibrium boratetransesterification reaction takes place readily so that some fractionof these other hydroxyl-containing compounds form temporary borateesters. This increases the crosslink density of the polymer as it forms,while maintaining an optically clear solution. This is accompanied by anincrease in the viscosity of the mixture. An increased crosslink densityalso results in a reduction in the gel time, which causes an increase inthe rate of polymerization (the Trommsdorff effect). Reductions in geltime thus reduce the time to cure. Time to cure may be measured bydifferential photocalorimetry using the equipment and method describedin Example 9 herein. In one embodiment the time to reach 90% cure isless than about 3 minutes and in other embodiments the time to reach 95%cure is less than about 3.6 minutes. In another embodiment the time toreach either 90% or 95% cure is decreased by at least about 10% ascompared to a lens formed without including at least one borate. Inanother embodiment, the time to cure is reduced by at least 20%.

The beneficial effects of borates can be realized in a number of ways.In one embodiment, a borate ester is added to the reaction mixture. Inanother embodiment, boric acid is added to the reaction mixture. In yetanother embodiment, boric anhydride is added. Both boric acid and boricanhydride are believed to form borate esters in situ by undergoing acondensation reaction with the free hydroxyl groups in the components.In some embodiments, it may be advantageous to promote the in situformation of borate by heating the mixture and/or applying a vacuum toremove the condensation byproduct (e.g. water). Suitable temperaturesand pressures for creating the borate esters in situ include from about25 to about 100° C. and a wide range of pressures.

In yet another embodiment, at least a portion of at least one of thehydroxyl containing components may be “preloaded” by reacting its freehydroxyl groups with a borate compound to preform a borate ester. Whenthe preloaded component is exposed to the other hydroxyl-containingcomponents in the reaction mixture, further borate transesterificationsreaction can occur.

Various methods for quantifying the viscosity of a fluid are known inthe art. For example, a glass tube viscometer (e.g. Ostwald or Ubbelohdeviscometer) may be used. Alternatively, a rotational viscometer, such asthe commercially available MERLIN™ or Brookfield viscometers, may beused. In one embodiment, the borate causes at least a 10% increase inviscosity, relative to an identical mixture that lacks the borate. Inanother embodiment, the borates causes at least a 20% increase inviscosity. In yet another embodiment, at least a 30% increase is causedby the addition of the borate. In still another embodiment, at least is50% increase in viscosity is observed.

In one embodiment, the invention pertains to an intermediate contactlens material that includes a cured, optically clear contact lensmaterial. The material is the polymerization product of the at least onehydrophilic component and the at least one silicone component, at leastone of which has a hydroxyl moiety, which may be part of a borate esteror may exist in —C—O—H form. Also present in the cured material is theresidual borate ester discussed elsewhere in this specification. Thisborate is not permanently incorporated into the polymeric material and,is typically removed from the polymerization product via hydrolysis orextraction. Methods of removing residual compounds from a cured contactlens material are known in the art. For example, the borates may beextracted by washing the material with solvents comprising at leasthydroxyl group, such as alcohols, water and mixtures thereof. In oneembodiment, where at least one alcohol is used, the alcohol is watersoluble. Examples of suitable solvents include water and lower alcohols,such as methanol, ethanol, n-propanol and isopropanol.

The lenses produced according to the above process have materialproperties that differ from those of a corresponding lens producedwithout the borate additive. For example, the lenses may be moreoptically clear. In some embodiments the % haze is less than 100%compared to a CSI lens, and in other embodiments less than about 40%.

Although the above discussion focuses on the use of the material in thefield of contact lenses, there are non-contact lens applications for thepresent invention. By way of illustration, and not limitation, otherapplications include biomaterial scaffolds, absorbent articles, drugdelivery particles, polymers and articles.

These examples do not limit the invention. They are meant only tosuggest a method of practicing the invention. Those knowledgeable incontact lenses as well as other specialties may find other methods ofpracticing the invention. However, those methods are deemed to be withinthe scope of this invention.

Haze is measured by placing a hydrated test lens in borate bufferedsaline in a clear 20×40×10 mm glass cell at ambient temperature above aflat black background, illuminating from below with a fiber optic lamp(Titan Tool Supply Co. fiber optic light with 0.5″ diameter light guideset at a power setting of 4-5.4) at an angle 66° normal to the lenscell, and capturing an image of the lens from above, normal to the lenscell with a video camera (DVC 1300C:19130 RGB camera with Navitar TVZoom 7000 zoom lens) placed 14 mm above the lens platform. Thebackground scatter is subtracted from the scatter of the lens bysubtracting an image of a blank cell using EPIX XCAP V 1.0 software. Thesubtracted scattered light image is quantitatively analyzed, byintegrating over the central 10 mm of the lens, and then comparing to a−1.00 diopter CSI Thin Lens®, which is arbitrarily set at a haze valueof 100, with no lens set as a haze value of 0. Five lenses are analyzedand the results are averaged to generate a haze value as a percentage ofthe standard CSI lens.

EXAMPLES

Examples 1 through 7, detailed elsewhere in this specification, show anincrease in the solution viscosity as additional borate is added.

Examples 8 to 11 show a decrease in the cure time of a silicone hydrogelcomponent mixture as the borate concentration is increased.

Examples 12 to 14 also show a decrease in the cure time of a differentsilicone hydrogel mixture as borate concentration is increased.

Examples 15 and 16 show that, in some cases, optical properties areenhanced by the addition of the borate additive.

Example 17 shows an increase in miscibility of the blend componentscaused by the addition of borate. This resulted in lens with improvedoptical properties.

Examples 18 and 19 quantify the reduction in cure time due to theaddition of borate for certain blends.

Exam- mmole μl B(OEt)₃ mmole % ple OH added BO BO/OH Clarity Viscosity 2(con- 6.6 0 0  0% Clear Low trol) 3 7.0 25 0.43 6.1%  Clear Slightlyviscous 4 7.5 50 0.88 12% Clear Very viscous 5 8.4 100 1.8 21% ClearVery viscous 6 10 200 3.5 35% Clear Very viscous 7 13 375 6.5 50%Slightly Very cloudy viscous

The term “mmole OH” refers to total moles hydroxyl, in a given reactivemixture, including hydroxyl groups that are free, and those that areincorporated into a borate ester. So in the above calculation, the mmoleOH may be calculated as follows. First the moles of OH in the silicone,diluent and hydrophilic components are calculated. The siliconecomponent is the macromer formed in Example 1. The molecular weight ofthe macromer of Example 1 is 13,550 g per mole. It has 30 OH groups permole, thus:

${\left( \frac{13550\mspace{14mu} g\mspace{14mu}{macromer}}{{mole}\mspace{14mu}{macromer}} \right)\left( \frac{1\mspace{14mu}{mole}\mspace{14mu}{macromer}}{30\mspace{14mu}{mole}\mspace{14mu}{OH}} \right)\left( \frac{1000\mspace{14mu}{mg}}{g} \right)\left( \frac{1\mspace{14mu}{mole}}{1000\mspace{14mu}{mmole}} \right)} = \frac{452\mspace{14mu}{mg}\mspace{14mu}{macromer}}{{mmole}\mspace{14mu}{OH}}$

The blend (5 g in Examples 2-7) which does not contain any diluent,before addition of borate contains 60% macromer, thus:

${\left( \frac{5\mspace{14mu} g\mspace{14mu}{blend}}{1} \right)\left( \frac{1000\mspace{14mu}{mg}}{1\mspace{14mu} g} \right)\left( \frac{60{\mspace{11mu}\;}g\mspace{14mu}{macromer}}{100{\mspace{11mu}\;}g\mspace{14mu}{blend}} \right)\left( \frac{{mmole}\mspace{14mu}{OH}}{452\mspace{14mu}{mg}\mspace{14mu}{macromer}} \right)} = \frac{6.6\mspace{14mu}{mmoles}\mspace{14mu}{OH}}{1}$

However, additional hydroxyl groups (in the form of borate esters) areadded with the B(OEt)₃. This additional amount of OH is the same as themmolar quantity of BO groups shown in the examples. The mmole OH columnis the sum of these two hydroxyl sources. Further details are providedwith the corresponding example.

In the examples that follow, certain abbreviations are used.

OH- mono-(3-methacryloxy-2-hydroxypropyloxy)propyl mPDMS terminated,mono-butyl terminated polydimethyl- siloxane (MW 612 g/mole) mPDMSmono-3-methacryloxypropyl terminated, mono-butyl terminatedpolydimethylsiloxane (MW 1000 g/mole) SiGMA 2-propenoic acid,2-methyl-,2-hydroxy-3-[3-[1,3,3,3- tetramethyl-1-[(trimethylsilyl)oxy]disiloxanyl]propoxy]propyl ester DMAN,N-dimethylacrylamide HEMA 2-hydroxyethyl methacrylate HEAA2-hydroxyethyl acrylamide GMA Glycerine mono-methacrylate TEGDMAtetraethyleneglycol dimethacrylate Norbloc2-(2′-hydroxy-5-methacrylyloxyethylphenyl)2H- benzotriazole PVP K-90polyvinyl pyrrolidone PAGMBE polyoxyalkyleneglycol derivatives sold asUnilube 50MB-5 by NOF Corporation CGI-819bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide Darocur2-hydroxy-2-methylpropiophenone 1173 Blue the reaction product ofReactive Blue 4 and HEMA, as Hema described in Example 4 of U.S. Pat.No. 5,944,853 TAA Tert-amyl alcohol TPME tri(propylene glycol) methylether D3O 3,7-dimethyl-3-octanol

Example 1 Preparation of HFM 30:30 Macromer

A sample of 50 g octamethylcyclotetrasiloxane was combined with 9.36 gof 1,3,5,7-tetramethylcyclotetrasiloxane, 1.96 g1,3-bis(3-methacryloxypropyl)tetramethyldisiloxane, 70 g dichloromethaneand 0.5 g trifluoromethanesulfonic acid in a round bottomed flask. Thismixture was stirred under nitrogen at room temperature for about 24hours. The mixture was washed with 75 ml saturated aqueous sodiumcarbonate. The bottom layer was washed with about 75 ml of water anddried over sodium sulfate. The mixture was filtered through Celite andthe solvent was removed under reduced pressure to give an intermediateproduct as a clear oil.

To 98 g of this intermediate was added 0.02 g of2,6-di-tert-butyl-4-methylphenol (BHT), 0.04 g potassium acetate, 100 mgof a 10% (wt) solution of chloroplatinic acid in isopropanol, 18.1 gallyl alcohol and about 100 g isopropanol. This mixture was heated undernitrogen to 50° C. for three hours. The mixture was cooled and filteredthrough Celite. The solvent was removed under reduced pressure at about8 Torr for about 3 hours to yield the product (HFM 130:30) as a clearoil.

Example 2 Control—0 M % OH Borate

A blend was made of 60 parts by weight HFM 130:30 (see Example 1) and 40parts N,N-dimethylacrylamide (DMA) with 0.23 parts CGI 819(bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide). A 5 g portion wasstirred and its viscosity was visually observed. The mixture was deemedto have low viscosity and a clear appearance.

Example 3 6 M % OH Borate

A 5 g portion of a blend was prepared in accordance with Example 2. Tothis mixture was added 25 μL triethyl borate (0.15 mmoles, 0.02145 g).The resulting mixture was deemed to be slightly more viscous than thecontrol of Example 2. The mixture formed a white precipitate uponaddition of the borate but the precipitate gradually disappeared withstirring.

Triethyl borate introduces 20.5 mmoles of OH functionality per gram.

${\left( \frac{{mole}\mspace{14mu}{B({OEt})}_{3}}{145.99\mspace{14mu} g\mspace{14mu}{B({OEt})}_{3}} \right)\left( \frac{3\mspace{14mu}{mole}\mspace{14mu}{OH}}{1\mspace{14mu}{mole}\mspace{14mu}{B({OEt})}_{3}} \right)\left( \frac{1000\mspace{14mu}{mmoles}}{mole} \right)} = \frac{20.5\mspace{14mu}{mmoles}\mspace{14mu}{OH}}{g\mspace{14mu}{B({OEt})}_{3}}$

Similar calculations for blends using the HFM (130:30) of Example 1shows the blend provides 2.21 mmole OH per gram. Analogous methods showtriethyl borate can provide 20.5 borate functionality (B—O bonds) pergram.

The mmoles of OH from a component per gram of blend can then bedetermined. The following calculation determines the mmol OH fromtriethyl borate, but HFM 130:30 can also be determined in a similarfashion.

${\left( \frac{20.5\mspace{14mu}{mmoles}\mspace{14mu}{OH}}{g\mspace{14mu}{B({OEt})}_{3}} \right)\left( \frac{0.858\mspace{14mu} g\mspace{14mu}{B({OEt})}_{3}}{{mL}\mspace{14mu}{B({OEt})}_{3}} \right)\left( \frac{1\mspace{14mu}{mL}}{1000\mspace{14mu}{\mu L}} \right)\left( \frac{25\mspace{14mu}{\mu L}\mspace{14mu}{B({OEt})}_{3}}{1} \right)\left( \frac{1}{5{\mspace{11mu}\;}g\mspace{14mu}{blend}} \right)} = \left( \frac{0.09\mspace{14mu}{mmoles}\mspace{14mu}{OH}\mspace{14mu}{from}\mspace{14mu}{B({OEt})}_{3}}{1{\mspace{11mu}\;}g\mspace{14mu}{blend}} \right)$

The resulting blend is therefore 6 molar % OH, measured relative to thehydroxyl functionality. The results are summarized in Table 1.

$\frac{0.09\mspace{14mu}{mmole}\mspace{25mu}{\text{B—O}/g}\mspace{14mu}{blend}}{1.41\mspace{14mu}{mmole}\mspace{14mu}{{OH}/g}\mspace{14mu}{blend}} = {\text{6M}\mspace{14mu}\%\mspace{14mu}{OH}}$

TABLE 1 Composition of Example 3 mmole mmole mmole mmole g/g of OH/gB—O/g OH/g B—O/g blend comp. component blend blend HFM 0.6 2.21 0 1.330.00 130: 30 DMA 0.4 0 0 0.00 0.00 triethyl 0.0042 20.5 20.5 0.09 0.09borate Total 1.41 0.09 (6.1M % OH)

Example 4 12 M % OH Borate

A 5 g portion of a blend was prepared in accordance with Example 2. Tothis mixture was added 50 μL triethyl borate (0.30 mmoles). Theresulting mixture was deemed to be significantly more viscous than thecontrol of Example 2. The mixture formed a white precipitate uponaddition of the borate but the precipitate gradually disappeared withstirring.

TABLE 2 Composition of Example 4 mmole mmole mmole mmole g/g of OH/gB—O/g OH/g B—O/g blend comp. component blend blend HFM 0.59 2.21 0 1.300.00 130: 30 DMA 0.4 0 0 0.00 0.00 triethyl 0.0085 20.5 20.5 0.17 0.17borate Total 1.48 0.17 (11.8M % OH)

Example 5 21 M % OH Borate

A 5 g portion of a blend was prepared in accordance with Example 2. Tothis mixture was added 100 μL triethyl borate (0.60 mmoles). Theresulting mixture was deemed to be significantly more viscous than thecontrol of Example 2. The mixture formed a white precipitate uponaddition of the borate but the precipitate gradually disappeared withstirring.

TABLE 3 Composition of Example 5 mmole mmole mmole mmole g/g of OH/gB—O/g OH/g B—O/g blend comp. component blend blend HFM 0.59 2.21 0 1.300.00 130: 30 DMA 0.39 0 0 0.00 0.00 triethyl 0.017 20.5 20.5 0.35 0.35borate Total 1.65 0.35 (21.1M % OH)

Example 6 34 M % OH Borate

A 5 g portion of a blend was prepared in accordance with Example 2. Tothis mixture was added 200 μL triethyl borate (1.20 mmoles). Theresulting mixture was deemed to be significantly more viscous than thecontrol of Example 2. The mixture formed a white precipitate uponaddition of the borate but the precipitate gradually disappeared withstirring.

TABLE 4 Composition of Example 6 mmole mmole mmole mmole g/g of OH/gB—O/g OH/g B—O/g blend comp. component blend blend HFM 130:30 0.58 2.210 1.28 0.00 DMA 0.39 0 0 0.00 0.00 triethyl 0.033 20.5 20 0.68 0.66borate Total 1.96 0.66 (33.7M % OH)

Example 7 50 M % OH Borate

A 5 g portion of a blend was prepared in accordance with Example 2. Tothis mixture was added 375 μL triethyl borate (2.20 mmoles). Theresulting mixture was deemed to be significantly more viscous than thecontrol of Example 2. The mixture formed a white precipitate uponaddition of the borate but the precipitate gradually diminished withstirring. The mixture remained slightly cloudy.

TABLE 5 Composition of Example 6 mmole mmole mmole mmole g/g of OH/gB—O/g OH/g B—O/g blend comp. component blend blend HFM 130:30 0.56 2.210 1.24 0.00 DMA 0.38 0 0 0.00 0.00 triethyl 0.06 20.5 20.5 1.23 1.23borate Total 2.47 1.23 (49.8M % OH)

Example 8 Preparation of Blend

A blend was made as shown in Table 6

TABLE 6 Component Weight percent HFM 130:30 (Example 1) 32.27% OH-mPDMS30.97% DMA 10.00% HEMA 14.06% TEGDMA 0.51% Norbloc 1.20% PVP K-90 10.99%

To this blend of components was added enough PAGMBE diluent such thatthe ratio of components to diluent was 90:10 by weight. To this mixturewas added 0.039 parts by weight CGI-819 per 100 parts blend. Portions ofthis blend were used in Examples 9 and 10.

Example 9 Control—0 molar % OH Borate

A portion of the blend from Example 8 was maintained without theaddition of a borate additive for comparison purposes. The kinetics ofthe photocure was evaluated using a TA Instruments 2920 Thermal AnalysisDifferential Scanning calorimeter (DSC) equipped with a mercury vaporlamp with a radiant intensity (after passing through a blue-violet glassfilter and a red-absorbing glass filter, both from Melles Griot) ofabout 2 mW/cm², a combination of visible and UV light.

About 10 mg of the sample was placed into an aluminum pan which wasplaced into the DSC. The chamber was purged with nitrogen for fiveminutes. The sample temperature was increased to 70° C. After a fiveminute hold period the sample was irradiated and the heat generated wasmeasured as a function of time. The results are shown in FIG. 1.

Example 10

1.2 parts triethyl borate was added to 100 parts of the blend fromExample 8. Upon addition, a white precipitate formed. The resultingmixture was stirred and allowed to stand overnight until it becameoptically clear. The mixture maintained a higher viscosity relative tothe control of Example 9.

The kinetics of the photocure were evaluated in accordance with theprocedure described in Example 9. The results in FIG. 2 showed a reduced“tail”, i.e. the mixture reached complete cure more quickly than theblend without borate.

Example 11 Preparation of Blend

A blend was made as shown in Table 7.

TABLE 7 Component Weight percent OH-mPDMS 55.00% DMA 19.53% PVP K-9012.00% HEMA 8.00% TEGDMA 3.00% Norbloc 2.20% CGI 819 0.25% Blue HEMA0.02%

The components above (55 parts) was added with 45 parts of a diluent(TPME). The blend had the following properties (0 M % OH borate).

TABLE 8 mmole mmole mmole mmole g/g of OH/g B—O/g OH/g B—O/g blend comp.comp. blend blend OH-mPDMS 0.3 1.63 0 0.49 0.00 DMA 0.11 0 0 0.00 0.00HEMA 0.044 7.7 0 0.34 0.00 TEGDMA 0.017 0 0 0.00 0.00 Blue HEMA 0.0001 00 0.00 0.00 Norbloc 0.012 0 0 0.00 0.00 PVP K-90 0.066 0 0 0.00 0.00TPME 0.45 4.85 0 2.18 0.00 triethyl 0 20.5 20.5 0.00 0.00 borate Total0.9991 3.01 0.00 (0M % OH)

Example 12 22.6 molar % OH

Using the blend of Example 11, 55 parts of the components was added with45 parts of a diluent made from 91% (wt) TPME and 8.9% triethyl borate.The resulting mixture was degassed by applying 40 mm Hg vacuum for 15minutes. Lenses were made by irradiating the mixture for 15 minutes atabout 1.3 mW/cm² using Philips TL 20 W/0.3 T fluorescent bulbs at 60° C.in plastic lens molds in a nitrogen environment. The kinetics of thephotocure were evaluated in accordance with the procedure described inExample 9 except in that the irradiation took place at 4 mW/cm². Theresults in FIG. 3 showed that addition of borate reduced the time tocomplete cure as compared to the same blend without borate. Table 9shows the calculations of grams component/gram blend, mmol OH/gcomponent, mmol B—O/g component, mmol OH/gm blend and mmol B—O/gm blend.The molar % OH is 22.6% and was calculated by dividing the total mmol—B—O—C— from the last column, by the total mmol OH in the second to lastcolumn.

TABLE 9 mmole mmole mmole mmole g/g of OH/g B—O/g OH/g B—O/g blend comp.comp. blend blend OH-mPDMS 0.3 1.63 0 0.49 0.00 DMA 0.11 0 0 0.00 0.00HEMA 0.044 7.7 0 0.34 0.00 TEGDMA 0.017 0 0 0.00 0.00 Blue HEMA 0.0001 00 0.00 0.00 Norbloc 0.012 0 0 0.00 0.00 PVP K-90 0.066 0 0 0.00 0.00TPME 0.41 4.85 0 1.99 0.00 triethyl 0.04 20.5 20.5 0.82 0.82 borateTotal 0.9991 3.64 0.82

Example 13 47.7 M % OH Borate

Example 14 was substantially identical to Example 12 except in that thediluent was made from 76% (wt) TPME and 24% (wt) triethylborate.

The kinetics of the photocure were evaluated in accordance with theprocedure described in Example 9 except in that the irradiation tookplace at 4 mW/cm².

The results in FIG. 3 showed that addition of borate reduced the time tocomplete cure as compared to the same blend without borate. Thecalculations of grams component/gram blend, mmol OH/g component, mmolB—O/g component, mmol OH/gm blend and mmol B—O/gm blend are shown inTable 10. The molar % OH is 47.7%

TABLE 10 mmole mmole mmole mmole g/g of OH/g B—O/g OH/g B—O/g blendcomp. comp. blend blend OH-mPDMS 0.3 1.63 0 0.49 0.00 DMA 0.11 0 0 0.000.00 HEMA 0.044 7.7 0 0.34 0.00 TEGDMA 0.017 0 0 0.00 0.00 Blue HEMA0.0001 0 0 0.00 0.00 Norbloc 0.012 0 0 0.00 0.00 PVP K-90 0.066 0 0 0.000.00 TPME 0.34 4.85 0 1.65 0.00 triethyl 0.11 20.5 20.5 2.26 2.26 borateTotal 0.9991 4.73 2.26

Examples 15 and 16 GMA-Borate—Improved Blend Miscibility

Two blends were prepared, as shown in Table 11, one using GMA (Example15) and the other using GMA-borate (Example 16). The GMA-borate was madeby combining 292 wt. parts triethylborate (Aldrich) and 380 parts GMA (a2 to 3 mole ratio, respectively) and removing the resulting ethanolusing a rotary evaporator at 50° C. under high vacuum for 1 hour, or toconstant mass, to yield a new compound, GMA-borate. The blend usingGMA-borate was filtered through glass wool to remove observed smallamount of precipitate that formed in this formulation.

TABLE 11 GMA/GMA-Borate Blends Example 15 Example 16 Components (wt %)(wt %) GMA 20 0 GMA-Borate 0 20 TRIS 40 40 DMA 6.7 6.7 TAA 33 33 Darocur1173 0.3 0.3 M % OH 0% 38.6%

Nitrogen was bubbled through each blend for 5 minutes, and the sampleswere allowed to sit open in a glove box with a nitrogen atmosphere for 2hours. Plastic molds were filled in the glove box and placed about 3inches under Philips TL09 20 W bulbs. The lenses were cured in anitrogen atmosphere at room temperature for 30 minutes. The lenses werethen leached, first, in a 50% isopropanol: 50% borate buffered salinesolution for 30 minutes, then in three cycles of 100% isopropanol for 30minutes each, next in 50% isopropanol: 50% borate buffered salinesolution for 30 minutes, and lastly, in 3 cycles of 100% borate bufferedsaline solution for 30 minutes each. The lenses from Example 15 (whichlacked borate) were white and the lenses from Example 16 (which includedthe borate additive) were clear. The calculations of gramscomponent/gram blend, mmol OH/g component, mmol B—O/g component, mmolOH/gm blend and mmol B—O/gm blend are shown in Tables 12 and 13. Themolar % OH are 0% for Example 15 and 38.4% for Example 16.

TABLE 12 Example 15 mmole mmole mmole mmole g/g of OH/g B—O/g OH/g B—O/gblend comp. comp. blend blend GMA 0.2 12.5 0 2.50 0.00 GMA-borate 0 11.811.8 0.00 0.00 TRIS 0.4 0 0 0.00 0.00 DMA 0.067 0 0 0.00 0.00 TAA 0.3311.4 0 3.76 0.00 Darocure 0.003 6.1 0 0.02 0.00 1173 Total 1 6.28 0.00

TABLE 13 Example 16 mmole mmole g/g in mmole mmole OH/g B—O/g blend OH/gB—O/g blend blend GMA 0 12.5 0 0.00 0.00 GMA-borate 0.2 11.8 11.8 2.362.36 TRIS 0.4 0 0 0.00 0.00 DMA 0.067 0 0 0.00 0.00 TAA 0.33 11.4 0 3.760.00 Darocure 0.003 6.1 0 0.02 0.00 1173 Total 1 6.14 2.36

Examples 17-25 HEAA-Borate—Improved Miscibility by Reducing the Amountof Diluent Needed for a Clear Lens

HEAA-borate was made by combining three moles HEAA with one moletriethylborate. Ethanol was removed using a rotary evaporator at 50° C.under high vacuum for 1 hour, or to constant mass, to yield a newcompound, HEAA-borate. Various blends were prepared as shown in Table14.

TABLE 14 HEAA and HEAA-Borate Blends Ex 17 Ex 18 Ex 19 Ex. 20 Ex. 21 Ex.22 Ex. 23 Ex 24 Ex. 25 Components (wt %) (wt %) (wt %) (wt %) (wt %) (wt%) (wt %) (wt %) (wt %) HEAA 39.5  35.5  31.5  27.5  0.0 0.0 0.0 0.0 0.0HEAA-Borate 0.0 0.0 0.0 0.0 39.5 37.5 35.5 31.5 27.5 SiGMA 59.2  53.2 47.2  41.2  59.2 56.2 53.2 47.2 41.2 TAA 0   10   20   30   0 5 10 20 30EGDMA 1   1   1   1   1 1 1 1 1 Darocur1173 0.3 0.3 0.3 0.3 0.3 0.3 0.30.3 0.3 M % OH 0% 0% 0% 0% 70.4% 62.6% 55.6% 44.1% 34.8% Blend No YesYes Yes Yes Yes Yes Yes Yes Miscible Lens Clarity N/A White Clear ClearWhite Slight Clear Clear Clear Haze

The HEAA and HEAA-borate blends, were degassed in a vacuum desiccator at40 mbar for approximately 30 minutes. Plastic molds were filled in theglove box and placed about 3 inches under Philips TL09 20 W bulbs. Thelenses were cured in a nitrogen atmosphere at room temperature for 30minutes. The lenses were leached, first, in a 50% isopropanol: 50%borate buffered saline solution for 30 minutes, then in three cycles of100% isopropanol for 30 minutes each, next in 50% isopropanol: 50%borate buffered saline solution for 30 minutes, and lastly, in 3 cyclesof 100% borate buffered saline solution for 30 minutes each. The clarityof the blends and lenses are described in Table 14. Example 17 (whichlacks borate) was not miscible, and no lenses were made from the blendof Example 17. The corresponding borate blend (Example 25) was miscible.Example 18 (lacking borate) formed a white lens, whereas thecorresponding borate blend (Example 23) formed a clear lens. Thecalculations of grams component/gram blend, mmol OH/g component, mmolB—O/g component, mmol OH/gm blend and mmol B—O/gm blend. The molar % OHfor Examples 17-20 are 0. The molar % OH for Examples 21—are 70%, 62.2%, 62.2%, 43.8% and 34.6% respectively.

TABLE 15 Example 17 mmole mmole mmole mmole g/g in OH/g B—O/g OH/g B—O/gblend comp. comp. blend blend HEAA 0.395 8.7 0 3.44 0.00 HEAA-borate 08.5 8.5 0.00 0.00 SiGMA 0.592 2.4 0 1.42 0.00 EGDMA 0.01 0 0 0.00 0.00TAA 0 11.4 0 0.00 0.00 Darocure 0.003 6.1 0 0.02 0.00 1173 Total 1 4.880.00

TABLE 16 Example 18 mmole mmole mmole mmole g/g in OH/g B—O/g OH/g B—O/gblend comp. comp. blend blend HEAA 0.355 8.7 0 3.09 0.00 HEAA-borate 08.5 8.5 0.00 0.00 SiGMA 0.532 2.4 0 1.28 0.00 EGDMA 0.01 0 0 0.00 0.00TAA 0.1 11.4 0 1.14 0.00 Darocure 0.003 6.1 0 0.02 0.00 1173 Total 15.52 0.00

TABLE 17 Example 19 mmole mmole mmole mmole g/g in OH/g B—O/g OH/g B—O/gblend comp. comp. blend blend HEAA 0.315 8.7 0 2.74 0.00 HEAA-borate 08.5 8.5 0.00 0.00 SiGMA 0.472 2.4 0 1.13 0.00 EGDMA 0.01 0 0 0.00 0.00TAA 0.2 11.4 0 2.28 0.00 Darocure 0.003 6.1 0 0.02 0.00 1173 Total 16.17 0.00

TABLE 18 Example 20 mmole mmole mmole mmole g/g in OH/g B—O/g OH/g B—O/gblend comp. comp. blend blend HEAA 0.275 8.7 0 2.39 0.00 HEAA-borate 08.5 8.5 0.00 0.00 SiGMA 0.412 2.4 0 0.99 0.00 EGDMA 0.01 0 0 0.00 0.00TAA 0.3 11.4 0 3.42 0.00 Darocure 0.003 6.1 0 0.02 0.00 1173 Total 16.82 0.00

TABLE 19 Example 21 mmole mmole mmole mmole g/g in OH/g B—O/g OH/g B—O/gblend comp. comp. blend blend HEAA 0 8.7 0 0.00 0.00 HEAA-borate 0.3958.5 8.5 3.36 3.36 SiGMA 0.592 2.4 0 1.42 0.00 EGDMA 0.01 0 0 0.00 0.00TAA 0 11.4 0 0.00 0.00 Darocure 0.003 6.1 0 0.02 0.00 1173 Total 1 4.803.36

TABLE 20 Example 22 mmole mmole g/g in OH/g mmole mmole OH/g B—O/g blendcomp. B—O/g comp. blend blend HEAA 0 8.7 0 0.00 0.00 HEAA-borate 0.3758.5 8.5 3.19 3.19 SiGMA 0.562 2.4 0 1.35 0.00 EGDMA 0.01 0 0 0.00 0.00TAA 0.05 11.4 0 0.57 0.00 Darocure 0.003 6.1 0 0.02 0.00 1173 Total 15.12 3.19

TABLE 21 Example 23 mmole mmole g/g in OH/g mmole mmole OH/g B—O/g blendcomp. B—O/g comp. blend blend HEAA 0 8.7 0 0.00 0.00 HEAA-borate 0.3558.5 8.5 3.02 3.02 SiGMA 0.532 2.4 0 1.28 0.00 EGDMA 0.01 0 0 0.00 0.00TAA 0.1 11.4 0 1.14 0.00 Darocure 0.003 6.1 0 0.02 0.00 1173 Total 15.45 3.02

TABLE 22 Example 24 mmole mmole g/g in OH/g mmole mmole OH/g B—O/g blendcomp. B—O/g comp. blend blend HEAA 0 8.7 0 0.00 0.00 HEAA-borate 0.3158.5 8.5 2.68 2.68 SiGMA 0.472 2.4 0 1.13 0.00 EGDMA 0.01 0 0 0.00 0.00TAA 0.2 11.4 0 2.28 0.00 Darocure 0.003 6.1 0 0.02 0.00 1173 Total 16.11 2.68

TABLE 23 Example 25 g/g in mmole mmole mmole OH/g mmole B—O/g blend OH/gB—O/g blend blend HEAA 0 8.7 0 0.00 0.00 HEAA-borate 0.275 8.5 8.5 2.342.34 SiGMA 0.412 2.4 0 0.99 0.00 EGDMA 0.01 0 0 0.00 0.00 TAA 0.3 11.4 03.42 0.00 Darocure 0.003 6.1 0 0.02 0.00 1173 Total 1 6.76 2.34

Example 26-31 Quantified Relationship Between Cure Time and BorateConcentration

A. Formulation A with Borate Diluent

Various blends were prepared as shown in Table 24. D3O-Borate was formedby combining 3 moles D3O with one mole trimethylborate. Methanol wasremoved using a rotary evaporator at 50° C. under high vacuum for 1hour, or to constant mass, to yield a new compound, D3O-Borate. The %borate diluent refers to the percent of the total diluent used that isborate diluent. Blend components were added to a vial and rolled on ajarroller for about 24 hours, or until all solids had fully dissolved.

TABLE 24 Ex. 27 Ex. 28 Ex. 29 Ex. 30 Ex. 31 100% 75% 50% 25% 0% BorateBorate Borate Borate Borate Components Diluent Diluent Diluent DiluentDiluent SiGMA 21.55%* 21.55%  21.55%  21.55%  21.55%  DMA 18.46% 18.46%  18.46%  18.46%  18.46%  mPDMS 23.85%  23.85%  23.85%  23.85% 23.85%  HEMA 4.62% 4.62% 4.62% 4.62% 4.62% PVP K90 5.38% 5.38% 5.38%5.38% 5.38% Norbloc 1.54% 1.54% 1.54% 1.54% 1.54% TEGDMA 1.15% 1.15%1.15% 1.15% 1.15% Irgacure 0.37% 0.37% 0.37% 0.37% 0.37% 1850 D3O-Borate23.08%  17.31%  11.54%  5.77% 0.00% D3O 0.00% 5.77% 11.54%  17.31% 23.08%  M % OH 62.7% 47.0% 31.4% 15.7%   0% *Table values are weightpercent

The calculations of grams component/gram blend, mmol OH/g component,mmol B—O/g component, mmol OH/gm blend and mmol B—O/gm blend.

TABLE 25 Example 27 mmole mmole g/g in mmole B—O/g mmole OH/g B—O/gblend OH/g comp comp blend blend mPDMS 0.239 0 0 0.00 0.00 HEMA 0.0467.7 0 0.35 0.00 SiGMA 0.216 2.4 0 0.52 0.00 DMA 0.185 0 0 0.00 0.00 PVPK-90 0.054 0 0 0.00 0.00 TEGDMA 0.012 0 0 0.00 0.00 Norbloc 0.015 0 00.00 0.00 Irgacure 1850 0.0037 4.5 0 0.02 0.00 D3O 0 6.3 0 0.00 0.00D3O-borate 0.231 6.2 6.2 1.43 1.43 Total 1.00 2.32 1.43The lenses of Example 27 had a molar % OH of 61.7%.

TABLE 26 Example 28 mmole mmole mmole g/g in OH/g B—O/g mmole OH/g B—O/gblend comp. comp. blend blend mPDMS 0.239 0 0 0.00 0.00 HEMA 0.046 7.7 00.35 0.00 SiGMA 0.216 2.4 0 0.52 0.00 DMA 0.185 0 0 0.00 0.00 PVP K-900.054 0 0 0.00 0.00 TEGDMA 0.012 0 0 0.00 0.00 Norbloc 0.015 0 0 0.000.00 Irgacure 1850 0.0037 4.5 0 0.02 0.00 D3O 0.058 6.3 0 0.37 0.00D3O-borate 0.173 6.2 6.2 1.07 1.07 Total 1.00 2.33 1.07The lenses of Example 28 had a molar % OH of 46.1%.

TABLE 27 Example 29 mmole mmole g/g in mmole B—O/g mmole OH/g B—O/gblend OH/g comp comp blend blend mPDMS 0.239 0 0 0.00 0.00 HEMA 0.0467.7 0 0.35 0.00 SiGMA 0.216 2.4 0 0.52 0.00 DMA 0.185 0 0 0.00 0.00 PVPK-90 0.054 0 0 0.00 0.00 TEGDMA 0.012 0 0 0.00 0.00 Norbloc 0.015 0 00.00 0.00 Irgacure 1850 0.0037 4.5 0 0.02 0.00 D3O 0.115 6.3 0 0.72 0.00D3O-borate 0.115 6.2 6.2 0.71 0.71 Total 1.00 2.33 0.71The lenses of Example 29 had a molar % OH of 30.6%.

TABLE 28 Example 30 mmole mmole g/g in mmole B—O/g mmole OH/g B—O/gblend OH/g comp comp blend blend mPDMS 0.239 0 0 0.00 0.00 HEMA 0.0467.7 0 0.35 0.00 SiGMA 0.216 2.4 0 0.52 0.00 DMA 0.185 0 0 0.00 0.00 PVPK-90 0.054 0 0 0.00 0.00 TEGDMA 0.012 0 0 0.00 0.00 Norbloc 0.015 0 00.00 0.00 Irgacure 1850 0.0037 4.5 0 0.02 0.00 D3O 0.173 6.3 0 1.09 0.00D3O-borate 0.058 6.2 6.2 0.36 0.36 Total 1.00 2.34 0.36The lenses of Example 30 had a molar % OH of 15.4%.

TABLE 29 Example 31 mmole mmole g/g in mmole B—O/g mmole OH/g B—O/gblend OH/g comp comp. blend blend mPDMS 0.239 0 0 0.00 0.00 HEMA 0.0467.7 0 0.35 0.00 SiGMA 0.216 2.4 0 0.52 0.00 DMA 0.185 0 0 0.00 0.00 PVPK-90 0.054 0 0 0.00 0.00 TEGDMA 0.012 0 0 0.00 0.00 Norbloc 0.015 0 00.00 0.00 Irgacure 1850 0.0037 4.5 0 0.02 0.00 D3O 0.231 6.3 0 1.46 0.00D3O-borate 0 6.2 6.2 0.00 0.00 Total 1.00 2.34 0.00The lenses of Example 31 had a molar % OH of 0%.

Examples 32-33 Formulation with Borate Components and Diluent

A blend of 141 wt. parts trimethylborate, 402 parts D3O, 81 parts HEMA,and 376 parts SiGMA (a mole ratio of 10:19:6:5, respectively) wasprepared. Methanol was removed using a rotary evaporator at 50° C. underhigh vacuum for 1 hour, or to constant mass, to yield a new blend,referred to as SHD-Borate. Two Formulation A blends using SHD-Boratewere prepared as described in Table 30. Blend components were added to avial and rolled on ajar roller for about 24 hours, or until all solidshad fully dissolved.

TABLE 30 Blends with Borate Components/Diluent Ex. 33-100% Ex. 32-50%Borate Borate Components Components/Diluent Components/DiluentSHD-Borate 24.62% 49.24% SiGMA 10.77%  0.00% DMA 18.47% 18.47% mPDMS23.85% 23.85% HEMA  2.31%  0.00% PVP K90  5.38%  5.38% Norbloc  1.54% 1.54% TEGDMA  1.15%  1.15% Irgacure 1850  0.37%  0.37% D3O 11.54% 0.00% M % OH   50%   100% *Table values are weight percent

Examples 34-39

Formulations of Examples 34-39 were placed with vial caps removed in anitrogen filled box for at least 1 hour. Plastic molds were filled inthe glove box and placed about three inches under Philips TL03 20 Wbulbs for 30 minutes. The lenses were cured in a nitrogen atmosphere atroom temperature for 30 minutes. The lenses were leached, first, in a50% isopropanol: 50% borate buffered saline solution for 30 minutes,then in three cycles of 100% isopropanol for 30 minutes each, next in50% isopropanol: 50% borate buffered saline solution for 30 minutes, andlastly, in 3 cycles of 100% borate buffered saline solution for 30minutes each. The lenses from blends 10-15 were clear and the lensesfrom blend 16 were white.

The cure characteristics for the Formulation A blends described inTables 7 and 8 were studied using a TA Instruments model Q100 photo-DSCequipped with a universal LED module from Digital Light Labs modelnumber ULM-1-420. Samples were placed on the stage, with nitrogenflushing, and equilibrated at 25° C. for 5 minutes, then 70° C. for 5minutes, and then photocure was initiated providing 4 mW/cm². Basecurves were plotted using sigmoidal correction. The cure times werecalculated using TA Universal Analysis 2000 software. Each blend wastested several times and the values in the table represent the averagesof between 2 and 4 runs. The enthalpy, time to peak exotherm, and timeto 25, 50, 75, 90, and 95 percent cure are shown in table 9.

The time to various percents cure is calculated by integrating the areaunder the photo-DSC curve. When the cure is complete the curve returnsto the same baseline level as before the cure lamp is turned on.Sometimes the level of this line returns to a level slightly greater orless than the original level. In this case a sigmoidal baselinecorrection should be applied. A sigmoidal baseline is an s-shaped linethat changes in level and/or slope before or after a peak. The baselineis adjusted for the fraction reacted (alpha) versus time. A sigmoidalbaseline initially is calculated as a straight line from peak start topeak end. It is then recalculated for each data point between the peaklimits as the weighted average between the projected horizontal ortangent baselines at peak start and end. The weighting factors for agiven point are: (1) one minus alpha times the initial baseline and (2)alpha times the final baseline. The area is then recalculated with thenew baseline. If the new area differs from the previous area by morethan one percent, the area is recalculated and the sigmoidal curveshifted repeatedly until two consecutive calculations of the area differby no more than one percent. The software used to generate the databelow was Universal Analysis 2000 for Windows 2000/XP/Vista, Version4.5A, Build 4.5.0.5, but DSC instruments from various manufacturerstypically have equivalent sigmoidal baseline correcting capabilities.)

TABLE 31 Formulation A Borate Photo-DSC Results Time to Time to Time toTime to Time to Cure Time to Enthalpy 25% Cure 50% Cure 75% Cure 90%Cure 95% Cure Ex. # Averages Peak (min) (J/g) (min) (min) (min) (min)(min) 34 0% D3O- 0.75 136.80 0.62 1.18 1.75 2.29 2.74 Borate 35 25% D3O-1.06 128.33 0.58 1.04 1.50 1.94 2.27 Borate 36 50% D3O- 0.91 113.70 0.550.92 1.31 1.70 2.02 Borate 37 75% D3O- 0.89 131.70 0.54 0.88 1.23 1.591.87 Borate 38 100% D3O- 0.80 136.40 0.50 0.80 1.10 1.42 1.69 Borate 3950% SHD- 0.72 150.70 0.43 0.70 0.96 1.20 1.35 Borate

These results show that by adding an increasing amount of the D3O-boratediluent, the cure time is reduced. It also shows that by adding borateto both the components and the diluent (Example 39 50% SHD-borate), aneven faster cure can be achieved. Comparing the values at 95% cure, the50% SHD-borate samples (Example 39) decreases the cure time by slightlymore than 50 percent and the 100% borate diluent sample (Example38)decreases cure time by about 38 percent.

Lenses were submitted for Dk, DCA, water content and mechanicals testingto determine if the addition of borate had any adverse effects on lensproperties. These results, given in Table 32, show that borate haslittle or no effect on these lens properties.

TABLE 32 Formulation A-Borate Lens Characteristics Ex. 34- Ex 35- Ex 36-Ex. 37- Ex. 38- Ex. 39- 100% 75% 50% 25% 0% 50% Borate Lens BorateBorate Borate Borate Borate Components/ Characteristics Diluent DiluentDiluent Diluent Diluent Diluent Water Content  38 ± 0.2  37 ± 0.2  37 ±0.4  37 ± 0.2  38 ± 0.2  38 ± 0.2 (%) Dk (barrers) 109 106 113 112 111107 Modulus (psi) 105 ± 10 104 ± 11 98 ± 2 105 ± 9  93 ± 7 96 ± 7Elongation (%) 210 ± 53 258 ± 55 239 ± 56 219 ± 52 248 ± 60 260 ± 51Tensile Strength 106 ± 26 129 ± 22 116 ± 30 112 ± 29 114 ± 34 130 ± 39(psi) Toughness 121 ± 48 168 ± 53 147 ± 61 131 ± 52 149 ± 67 169 ± 67(in#/in{circumflex over ( )}3) DCA  61 ± 11 60 ± 9  54 ± 14  73 ± 10  75± 10 101 ± 11

The addition of borate to the Formulation A blend decreased cure time byup to 50% without adversely affecting the lens properties.

Example 40-43 Formulation B-Borate

A: Formulation B with Borate Diluent.

TPME-borate was formed by combining three moles TPME with one moletrimethylborate. Methanol was removed using a rotary evaporator at 50°C. under high vacuum for 1 hour, or to constant mass to yield a newcompound, TPME-Borate. Various blends were prepared as described inTable 11. Several Formulation B blends using TPME-Borate were preparedas described in Table 11. Decanoic acid is from KIC Chemicals Inc. The %borate diluent refers to the percent of the total hydroxyl-functionaldiluent used that is introduced as a borate. Blend components were addedto a vial and rolled on ajar roller until all solids had fullydissolved.

TABLE 33 Formulation B Blends with Borate Diluent Ex. 40 Ex. 41- Ex. 42-Ex. 43- -0% 50% 75% 100% Borate Borate Borate Borate Component DiluentDiluent Diluent Diluent OH-mPDMS 30.26%  30.26%  30.26%  30.26%  DMA10.74%  10.74%  10.74%  10.74%  HEMA 4.40% 4.40% 4.40% 4.40% TPME-Borate0.00% 12.40%  18.54%  24.74%  TPME 24.74%  12.34%  6.20% 0.00% Decanoicacid 20.26%  20.26%  20.26%  20.26%  TEGDMA 1.65% 1.65% 1.65% 1.65% PVPK90 6.60% 6.60% 6.60% 6.60% Norbloc 1.21% 1.21% 1.21% 1.21% Irgacure 8190.14% 0.14% 0.14% 0.14% M % OH   0% 29.5% 44.3% 59.1% *Table values areweight percent

Formulation B blends of Examples 40-43 were placed with vial capsremoved in a nitrogen filled box for at least 1 hour. Plastic molds werefilled in the glove box and placed about three inches under Philips TL0320 W bulbs for 30 minutes. The lenses were cured in a nitrogenatmosphere at room temperature for 30 minutes. The lenses were thenleached, first, in a 50% isopropanol: 50% borate buffered salinesolution for 30 minutes, then in 3 cycles of 100% borate buffered salinesolution for 30 minutes each. The lenses from these blends were clear.

The cure characteristics for the Formulation B blends described in Table34 were studied using a TA Instruments model Q100 photo-DSC as inexample 3. The enthalpy, time to cure, and time to 25, 50, 75, 90, and95 percent cure are shown in Table 35. Each blend was tested severaltimes and the values in the table represent the averages of between 2and 4 runs.

TABLE 34 Formulation B Borate Photo-DSC Results Time to Time to Time toTime to Time to Cure Time to Enthalpy 25% Cure 50% Cure 75% Cure 90%Cure 95% Cure Ex Averages Peak (min) (J/g) (min) (min) (min) (min) (min)40 0% TPME- 0.32 106.47 0.60 1.25 2.15 3.16 3.93 Borate 41 50% TPME-0.32 110.73 0.60 1.19 1.94 2.82 3.51 Borate 42 75% TPME- 0.36 104.600.57 1.10 1.75 2.53 3.19 Borate 43 100% TPME- 0.74 100.30 0.54 1.02 1.592.31 2.93 Borate

These results show that by adding an increasing amount of theTPME-borate diluent, the cure time is reduced. Comparing the values at95% cure, Example 43 (100% TPME-borate) decreases the cure time byslightly more than 25 percent compared to Example 40.

Lenses were submitted for Dk, DCA, water content and mechanicals testingto determine if the addition of borate had any adverse effects on lensproperties. These results, given in Table 35, show that borate haslittle or no effect on these lens properties.

TABLE 35 Formulation B-Borate Lens Characteristics Ex. 40- Ex. 41- Ex.42- Ex. 43- 0% 50% 75% 100% Lens Borate Borate Borate BorateCharacteristics Diluent Diluent Diluent Diluent Water   43 ± 0.1   43 ±0.2   43 ± 0.2   45 ± 0.5 Content (%) Dk (barrers) 93 91 93 94 Modulus(psi) 103 ± 7  117 ± 9  110 ± 9  97 ± 6 Elongation (%) 225 ± 46 216 ± 45223 ± 64 211 ± 74 Tensile Strength 104 ± 20 115 ± 25 113 ± 30  99 ± 34(psi) Toughness 132 ± 44 138 ± 52 143 ± 61 122 ± 70 (in#/in³) DCA  57 ±12  70 ± 10 55 ± 7  63 ± 11

By adding borate to the Formulation B blend we were able to achieve upto a 25% reduction in cure time without adversely affecting the lensproperties.

Example 44-47 Formulation B with Borate Components and No Diluent

A blend of 77 parts trimethylborate, 805 parts OH-mPDMS and 118 partsHEMA (a mole ratio of 10:18:12 respectively) was prepared. Methanol wasremoved using a rotary evaporator at 50° C. under high vacuum for 1hour, or to constant mass, to yield a new borate blend referred to asOHH-Borate. Several no diluent Formulation B blends using OHH-Boratewere prepared as described in Table 36. Blend components were added to avial and rolled on a jar roller until all solids had fully dissolved.

TABLE 36 Formulation B Blend with Borate Components Ex. 44- Ex. 45- Ex.46- Ex. 47- 0% 50% 75%% 100% Borate Borate Borate Borate ComponentComponents Components Components Components OH-mPDMS 55.0% 27.5% 13.7%0.0% HEMA 8.0% 4.0% 2.0% 0.0% OHH-Borate 0.0% 31.5% 47.3%  63% DMA 19.5%19.5% 19.5% 19.5%  TEGDMA 3.0% 3.0% 3.0% 3.0% PVP K90 12.0% 12.0% 12.0%12.0%  Norbloc 2.2% 2.2% 2.2% 2.2% Irgacure 819 0.3% 0.3% 0.3% 0.3%*Table values are weight percent

Formulation blends from Examples 44-47 were placed with vial capsremoved in a nitrogen filled box for at least 1 hour. Plastic molds werefilled in the glove box and placed about three inches under Philips TL0320 W bulbs for 30 minutes. The lenses were cured in a nitrogenatmosphere at room temperature for 30 minutes. The lenses were thenleached, first, in a 50% isopropanol: 50% borate buffered salinesolution for 30 minutes, then in 3 cycles of 100% borate buffered salinesolution for 30 minutes each. The lenses from these blends were clear.

The cure characteristics for the Formulation B blends described in Table36 were studied using a TA Instruments model Q100 photo-DSC as inexample 3. The enthalpy, time to cure, and time to 25, 50, 75, 90, and95 percent cure are shown in Table 37, below. Each blend was tested inseveral times and the values in the Table represent the averages ofbetween 2 and 4 runs.

TABLE 37 No Diluent Formulation B Borate Photo-DSC Results Time to Timeto Time to Time to Time to Cure Time to Enthalpy 25% Cure 50% Cure 75%Cure 90% Cure 95% Cure Ex Averages Peak (min) (J/g) (min) (min) (min)(min) (min) 44 0% OHH- 0.52 174.05 0.33 0.49 0.65 0.81 0.93 Borate 4550% OHH- 0.38 200.60 0.27 0.38 0.50 0.63 0.74 Borate 46 75% OHH- 0.39206.17 0.27 0.39 0.51 0.65 0.77 Borate 47 100% OHH- 0.41 178.30 0.290.43 0.57 0.74 0.90 Borate

These results show that the addition of borate reduces the time to cure.

Lenses were submitted for DK, DCA, water content and mechanicals testingto determine if the addition of borate had any adverse effects on lensproperties. These results, given in Table 16, show that borate haslittle or no effect on these lens properties.

TABLE 38 No Diluent Formulation B-Borate Lens Characteristics Ex 44- Ex45- Ex 46- Ex 47- 0% 50% 75%% 100% Lens Borate Borate Borate BorateCharacteristics Components Components Components Components Water  34 ±0.4   36 ± 0.3   33 ± 0.1   36 ± 0.1 Content (%) DK (barrers) 100 99 9894 Modulus (psi) 304 ± 27  263 ± 31 304 ± 30 248 ± 33 Elongation (%) 98± 24 111 ± 26 102 ± 30 121 ± 36 Tensile 145 ± 31  136 ± 28 154 ± 37 141± 32 Strength (psi) Toughness 82 ± 38  84 ± 33  91 ± 46  95 ± 51(in#/in{circumflex over ( )}3) DCA 93 ± 8  94 ± 3 101 ± 5  107 ± 7 

The addition of borate to the no diluent Formulation B blend reducedcure time without adversely affecting the lens properties.

Dynamic Mechanical Analysis

Blends 17 (borate free control) and 20 (with borate) were tested usingdynamic mechanical analysis. The results in FIGS. 4 and 5 show that themodulus of material made by curing a borate containing blend is higherthan the modulus made with the same blend made without borate. Thedetails of the testing protocols follows.

The photo-polymerization reaction was monitored with an ATS StressTechrheometer [ATS RheoSystems, 52 Georgetown Road, Bordentown, N.J. 08505]equipped with a photo-curing accessory, which consisted of atemperature-controlled cell with a quartz lower plate and an aluminumupper plate, and a 420 nm LED array [EXFO Photonic Solutions Inc., 2260Argentia Rd., Mississauga, ON L5N 6H7 CANADA] situated beneath thequartz plate. The intensity of the radiation, measured at the surface ofthe quartz window with an IL1400A radiometer and XRL140A sensor[International Light, Inc., 17 Graf Road, Newburyport, Mass. 01950], wasregulated at 5.0±0.1 mW/cm² with an electronic controller [AndoverCorporation, 4 Commercial Drive, Salem, N.H. 03079-2800 USA]. Thetemperature was controlled at 60.0±0.1° C.

After approximately 0.25 mL of the reactive component mix was placed onthe lower plate of the rheometer, the 25 mm diameter upper plate waslowered to 0.500±0.001 mm above the lower plate, where it was held untilafter the reaction reached the gel point. The sample was allowed toreach thermal equilibrium (˜5 minutes, determined by the leveling-off ofthe steady shear viscosity of the sample as it warmed up) before the LEDarray was turned on and the reaction begun. During this time, while thesample was reaching thermal equilibrium, the sample chamber was purgedwith nitrogen gas at a rate of 400 sccm. After this initial purge theoxygen level in the sample chamber was monitored at 0.2±0.1% with aCheckPoint O₂ sensor [PBI Dansensor, available from Topac, 101 DerbySt., #203 Hingham, Mass. 02043]. During the reaction the rheometercontinuously monitored the strain resulting from an applied dynamicstress (fast oscillation mode), where time segments of less than acomplete cycle were used to measure the strain at the applied sinusoidalstress (applied at a frequency of 1.0 Hz). The dynamic shear modulus(G′), loss modulus (G″), and gap height were monitored as a function ofexposure time. As the reaction proceeded the shear modulus increasedfrom <1 Pa to >0.1 MPa, and tan δ (=G″/G′) dropped from near infinity toless than 1. For many reactive crosslinking systems the gel point isdefined as the time at which tan δ=1 (the crossover point when G′=G″).At the time that G′ reached 100 Pa (shortly after the gel point), therestriction of the gap height on the upper plate was removed(Autotension Mode: Tension=0) so that the gap between the upper andlower plates could change as the reactive component mix shrank duringcure, and the stress due to shrinkage was kept at a minimum. Ameasurement of the change in gap provides an estimate of the amount ofshrinkage caused by the polymerization reaction.

After a 10-minute exposure the LED array was turned off (i.e., the curewas terminated), and a temperature sweep was run on the cured filmbetween the parallel plates of the rheometer. The temperature was rampedfrom 60° C. to 25° C. (1° C./min) at a frequency of 1.0 Hz and a shearstress of 3000 Pa to determine the glass transition temperature (Tg),subsequently heating from 25° C. to 120° C. and then cooling from 120°C. to 25° C. to observe any changes that may be caused by heating abovethe cure temperature, all at a frequency of 1 Hz, stress of 3000 Pa, andtemperature change of 1° C./min.

Frequency sweeps from 0.01 Hz to 40 Hz at a shear stress of 1000 Pa wererun at 60° C. and at 25° C. on the cured films to obtain mechanicalproperty spectra.

What is claimed is:
 1. A method of forming a silicone hydrogel materialcomprising the steps of: providing a mixture of polymerizable componentsthat includes at least one hydrophilic component and at least onesilicone component, wherein at least one of the polymerizable componentscontains a hydroxyl group, the mixture further including a sufficientamount of a borate to reduce cure time compared to an identical mixturethat lacks the borate, the borate being selected from either boricanhydride or a borate represented by formula:

where wherein R₁, R₂ and R₃ are independently selected from the groupconsisting of hydrogen; C1-C16 alkyl groups; C1-C16 alkyl groupssubstituted with O, Cl, N, or Br; polymerizable groups; ester groups,amide groups, ether groups, silicone components and hydrophiliccomponents, with the proviso that R₁, R₂, and R₃ comprise at most onehydroxyl group; curing the mixture to form a cured material.
 2. Themethod as recited in claim 1, wherein R₁, R₂ and R₃ are monovalent. 3.The method as recited in claim 1, wherein at least two of R₁, R₂ and R₃are divalent and, taken together, form a cyclic borate ester.
 4. Themethod as recited in claim 1, wherein at least one of R₁, R₂ and R₃comprises a polymerizable group.
 5. The method as recited in claim 1,wherein R₁, R₂ and R₃ are the same.
 6. The method as recited in claim 1,wherein the borate is selected from the group consisting of a borateester of methanol, ethanol, propanol, t-amyl alcohol,3-methyl-3-pentanol, 3,7-dimethyl-3-octanol, 2-hydroxyethylmethacrylate,tri(propylene glycol) methyl ether, 2-propenoic acid,2-methyl-,2-hydroxy-3-[3-[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]disiloxanyl]propoxy]propylester (SiGMA), mono-(3-methacryloxy-2-hydroxypropyloxy)propylterminated, mono-butyl terminated polydimethylsiloxane (OHmPDMS); andcombinations thereof.
 7. The method as recited in claim 5, wherein R₁,R₂ and R₃ are selected from the group consisting of n-propyl,iso-propyl, butyl and tert-butyl.
 8. The method as recited in claim 1,wherein the borate is selected from the group consisting of trimethylborate and triethyl borate.
 9. The method as recited in claim 1, whereinthe borate is boric acid.
 10. The method as recited in claim 1, whereinthe step of curing the mixture has a borate content of between 2 M % OHand 50 M % OH.
 11. The method as recited in claim 1, wherein the mixturehas a viscosity that is at least 10% greater than that of the identicalmixture that lacks the borate.
 12. The method as recited in claim 1,further comprising the step of removing at least half of the borate fromthe cured contact lens material.
 13. The method as recited in claim 1,wherein the cure time is reduced by at least 10% relative to theidentical mixture that lacks the borate.
 14. The method as recited inclaim 1, wherein the cure time is reduced by at least 25% relative tothe identical mixture that lacks the borate.
 15. The method as recitedin claim 1, wherein the cure time is reduced by at least 50% relative tothe identical mixture that lacks the borate.
 16. A method of forming anoptically clear material comprising the steps of: providing a mixture ofpolymerizable components that includes at least one hydrophiliccomponent and at least one silicone component wherein at least one ofthe polymerizable components contains a hydroxyl group, the mixturefurther including a sufficient amount of a borate to render theresulting cured material more optically clear compared to a curedmaterial formed from an identical mixture that lacks the borate, theborate being selected from either boric anhydride or a boraterepresented by formula:

wherein R₁, R₂, and R₃ are independently selected from the groupconsisting of hydrogen; C1-C16 alkyl groups; C1-C16 alkyl groupssubstituted with O, Cl, N, or Br; polymerizable groups; ester groups,amide groups, ether groups, silicone components and hydrophiliccomponents, with the proviso that R₁, R₂, and R₃ comprise at most onehydroxyl group; curing the mixture to form a cured, optically clearmaterial.